<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - materials - lightmap</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="main.css">
	</head>

	<body>

		<script type="x-shader/x-vertex" id="vertexShader">

			varying vec3 vWorldPosition;

			void main() {

				vec4 worldPosition = modelMatrix * vec4( position, 1.0 );
				vWorldPosition = worldPosition.xyz;

				gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

			}

		</script>

		<script type="x-shader/x-fragment" id="fragmentShader">

			uniform vec3 topColor;
			uniform vec3 bottomColor;
			uniform float offset;
			uniform float exponent;

			varying vec3 vWorldPosition;

			void main() {

				float h = normalize( vWorldPosition + offset ).y;
				gl_FragColor = vec4( mix( bottomColor, topColor, max( pow( max( h, 0.0 ), exponent ), 0.0 ) ), 1.0 );

			}

		</script>

		<script type="module">

			import * as THREE from '../build/three.module.js';

			import Stats from './jsm/libs/stats.module.js';

			import { OrbitControls } from './jsm/controls/OrbitControls.js';

			const SCREEN_WIDTH = window.innerWidth;
			const SCREEN_HEIGHT = window.innerHeight;

			let container, stats;
			let camera, scene, renderer;

			await init();
			animate();

			async function init() {

				container = document.createElement( 'div' );
				document.body.appendChild( container );

				// CAMERA

				camera = new THREE.PerspectiveCamera( 40, SCREEN_WIDTH / SCREEN_HEIGHT, 1, 10000 );
				camera.position.set( 700, 200, - 500 );

				// SCENE

				scene = new THREE.Scene();

				// LIGHTS

				const light = new THREE.DirectionalLight( 0xaabbff, 0.3 );
				light.position.x = 300;
				light.position.y = 250;
				light.position.z = - 500;
				scene.add( light );

				// SKYDOME

				const vertexShader = document.getElementById( 'vertexShader' ).textContent;
				const fragmentShader = document.getElementById( 'fragmentShader' ).textContent;
				const uniforms = {
					topColor: { value: new THREE.Color( 0x0077ff ) },
					bottomColor: { value: new THREE.Color( 0xffffff ) },
					offset: { value: 400 },
					exponent: { value: 0.6 }
				};
				uniforms.topColor.value.copy( light.color );

				const skyGeo = new THREE.SphereGeometry( 4000, 32, 15 );
				const skyMat = new THREE.ShaderMaterial( {
					uniforms: uniforms,
					vertexShader: vertexShader,
					fragmentShader: fragmentShader,
					side: THREE.BackSide
				} );

				const sky = new THREE.Mesh( skyGeo, skyMat );
				scene.add( sky );

				// RENDERER

				renderer = new THREE.WebGLRenderer( { antialias: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( SCREEN_WIDTH, SCREEN_HEIGHT );
				container.appendChild( renderer.domElement );
				renderer.outputEncoding = THREE.sRGBEncoding;

				// CONTROLS

				const controls = new OrbitControls( camera, renderer.domElement );
				controls.maxPolarAngle = 0.9 * Math.PI / 2;
				controls.enableZoom = false;

				// STATS

				stats = new Stats();
				container.appendChild( stats.dom );

				// MODEL

				const loader = new THREE.ObjectLoader();
				const object = await loader.loadAsync( "models/json/lightmap/lightmap.json" );
				scene.add( object );

				//

				window.addEventListener( 'resize', onWindowResize );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			//

			function animate() {

				requestAnimationFrame( animate );

				renderer.render( scene, camera );
				stats.update();

			}

		</script>

	</body>

</html>
